Abstract:
Genetic diversity is valuable for barley breeding programs, as it allows for the selection of
desirable traits for further improvement. Compared to the genetic resources available in
the gene bank and the ever-changing weather conditions, previous genetic diversity
studies on barley have not been sufficient. This study was therefore, conducted to assess
the extent of genetic variability and association of agronomic traits in barley genotypes at
Adet and Debark experimental stations during the 2023 main cropping season. Eighty-one
barley genotypes were evaluated using a 9x9 simple lattice design. The analysis of
variance revealed a high level of variability among barley genotypes. In Adet, all traits
exhibit high heritability. In Debark, traits like days to heading, grain filling period, plant
height, spike length, number of seeds per spike, thousand seeds weight, and leaf rust
severity had high heritability. Genotypic correlations showed a highly significant positive
association of grain yield with harvest index, aboveground biomass, grain filling period,
and thousand seeds weight at both locations. However, days to heading and leaf rust
severity had also a highly significant negative correlation with grain yield at both
locations. The path coefficient analysis in this study revealed high and favorable direct
effects of aboveground biomass and harvest index on grain yieldand days to heading and
leaf rust severity had also negative indirect effects throughgrain filling period,
aboveground biomass and harvest index on grain yield at both locations. In this study at
Adet, the first four principal components with eigenvalues greater than one accounted for
78.4% of the total variations among genotypes and the first five principal components with
eigenvalues greater than one accounted for 80.5% of the variation across the 14 traits
under study at Debark. Using hierarchical cluster analysis, the genotypes were grouped
into five clusters at each location, each with specific trait compositions. At Adet, cluster II
and IV showed the highest inter-cluster distance (75.0) followed by cluster II and III
(59.35), and cluster IV and V (59.2). Whereas at Debark, the highest inter-cluster distance
was observed between cluster III and V (103.98) followed by cluster III and IV (82.14),
and cluster I and III (71.84). The higher inter-cluster distance observed in this study
indicatesthe genetic diversity among the barley genotypes.This study also identified highyielding
genotypes (5, 9, 18, 32, 41, 50, 51, 53, 54, 60, 65, 68, 75) with a grain yield
potential from2681.2Kg/ha to 7291.6 Kg/ha at Debark and 80.5 kg/ha to 4631.8 kg/h at
Adet. These genotypes could be selected as potential varieties through selection and
evaluation or as parents for hybridizationprogram. Since it is a one-year result, however,
it is necessary to repeat the field experiment over years and across locations.